Voltage-active-clamping non-transformer-type single-phase photovoltaic inverter

A photovoltaic inverter and transformer technology, which is applied in the field of power electronics, can solve the problems of inability to completely eliminate common mode leakage current, unbalanced heating of switching devices, and reduce the overall efficiency of the inverter. The effect of reducing and reducing the loss

CN103956927AInactive Publication Date: 2014-07-30ZHEJIANG UNIV
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Patent Information

Authority / Receiving Office
CN · China
Current Assignee / Owner
Publication Date
2014-07-30
Estimated Expiration
Not applicable · inactive patent

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Abstract

The invention discloses a voltage-active-clamping non-transformer-type single-phase photovoltaic inverter which comprises an energy storage voltage dividing unit, a full-bridge inverting unit, an active-clamping unit and a filtering unit. When the inverter works, seven power switches with anti-parallel diodes work in an coordinated-action mode, so that when the inverter outputs the zero level, an alternating side carries out current following, the common-mode voltage is subjected to clamping to reach 1 / 2 of direct-current input voltage, accordingly, the fact that the common-mode voltage is constant in the whole cycle is guaranteed, then complete removing of common-mode current is achieved, and needed bus voltage is only half of a half-bridge type circuit. Meanwhile, unipolarity pulse width modulation is used, output current ripples are small, the size and the weight of a filter are reduced, meanwhile, loss on a magnetic element is lowered, on-off action frequency is low during an on-off cycle, switch loss is lowered, accordingly, the inverter is high in output efficiency, and the inverting efficiency as high as 98% can be obtained.
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Description

technical field

[0001] The invention belongs to the technical field of power electronics, and in particular relates to a transformerless single-phase photovoltaic inverter with voltage active clamping. Background technique

[0002] Nowadays, the problems of energy depletion and environmental pollution are becoming more and more serious, and the development and utilization of various new energy sources are getting more and more attention. Solar energy is currently one of the cleanest and most promising renewable energy sources for large-scale development and utilization, and its photovoltaic utilization has attracted widespread attention from all over the world. Solar photovoltaic power generation is the main development trend of solar photovoltaic utilization, and it will develop more and more rapidly in the future.

[0003] As the last or only energy conversion device in the photovoltaic power generation system, the inverter's efficiency and safety performance will directl...

Examples

Embodiment Construction

[0029] In order to describe the present invention more specifically, the technical solutions of the present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0030] Such as figure 2 As shown, a transformerless single-phase photovoltaic inverter with voltage active clamping includes: an energy storage voltage dividing unit, a full-bridge inverter unit, an active clamping unit and a filter unit. in:

[0031] The energy storage and voltage dividing unit is used to store energy and divide the input photovoltaic direct current to extract the midpoint voltage of the photovoltaic direct current output; in this embodiment, it includes a first input capacitor C dc1 , the second input capacitor C dc2. where the first input capacitor C dc1 The positive pole of the input DC terminal is connected to the positive pole of the input DC terminal, and the second input capacitor C dc2 The negative pole of the input DC term...